head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
A narrative horror game tested primarily by puzzle knowledge and sanity-resource management.

Optimization · Pure Optimization
A free-form fantasy RPG where skill-leveling and spell-craft builds dominate.
Amnesia: Rebirth leans Optimization (Pure Optimization); The Elder Scrolls IV: Oblivion leans Optimization (Pure Optimization).
The Elder Scrolls IV: Oblivion leans a little harder on execution, though the gap is small.
Amnesia: Rebirth
Stealth and evasion; no real twitch demands
The Elder Scrolls IV: Oblivion
Real-time swing and block, modest demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Amnesia: Rebirth
Enemies patrol fixed routes; no adaptive opponent
The Elder Scrolls IV: Oblivion
Scripted enemies
Amnesia: Rebirth leans a little harder on variance, though the gap is small.
Amnesia: Rebirth
Some encounter timing has variance; story rooms are fixed
The Elder Scrolls IV: Oblivion
Loot and level-scaling rolls
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Amnesia: Rebirth
Resource management, narrative puzzles and safe-path knowledge are solvable
The Elder Scrolls IV: Oblivion
Skill leveling, spell crafting, exploit-prone builds
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.